Ultramarine Blue Pigment Research Articles

Ultramarine blue pigment degradation in cementitious materials: a new approach to the phenomenon

The paper analyses the degradation process of commercial ultramarine blue pigments in cementitious materials. For this purpose, two commercial pigments (with and without a protective coating) in different solutions and cement pastes are studied incrementally. The results show that pigment degradation occurs due to an ion exchange phenomenon; during hydration high ion contents are released, calcium and potassium being the most aggressive for the pigment. Calcium distorts the unit cell; between the sodium of the pigment and the potassium in the medium a cation exchange phenomenon takes place. Both processes lead to the diffusion of sulphate and sulphide ions from the pigment to the medium causing loss of colour and the formation of ettringite.

Characterization of photoluminescent and Raman properties of ultramarine blue pigment variants with a novel multimodal approach

Ultramarine Blue (UB) pigment, derived from lapis lazuli, holds a significant place in the history of late medieval and Renaissance Europe, owing to its unusually bright colour and stability. Its prohibitive price, which equalled that of gold, meant that it was only used by estimated artists. In this work we present a non-invasive, multimodal approach to the characterization of the photoluminescent properties of different variants of the pigment. The ultimate goal of this research is to propose a protocol for the identification of UB in artworks thanks to the combination of Raman spectroscopy and time resolved-photoluminescence spectroscopy and imaging.

Influence of Compounding Parameters on Color Space and Properties of Thermoplastics with Ultramarine Blue Pigment.

The incorporation of thermoplastics with pigments imparts diverse aesthetic qualities and properties to colored thermoplastic products. The selection of pigment type and content, along with specific processing conditions, plays a pivotal role in influencing color properties and overall product performance. This study focuses on optimizing these parameters to ensure the desired color quality and product functionality. Two types of polypropylene copolymer (PPCP) with different melt flow rates (MFRs) and acrylonitrile butadiene styrene (ABS) were compounded with ultramarine blue pigment masterbatch (MB) in concentrations ranging from 1 to 5 wt.% using a twin-screw extruder. The compounding process was conducted at a constant screw speed of 200 rpm and a die temperature of 210 °C. The effects of screw speed and die temperature were investigated at a constant MB of 3 wt.%. Colored samples were fabricated by injection molding. Microscopic analysis revealed a well-dispersed pigment within the PPCP matrix when using the MB. Rheological properties, assessed through the power law index, confirmed effective pigment dispersion, facilitated by shear thinning behavior and controlled shear rate via the manipulation of screw speed and die temperature. The effects of masterbatch contents and processing conditions on color spaces were evaluated using CIELAB and CIELCH, with one-way ANOVA employed to identify statistical significance. Higher opacity in high-MFR PPCP and ABS resulted in increased lightness and color strength, surpassing low-MFR PPCP by 15-40% at equivalent MB contents. Masterbatch content emerged as a significant factor influencing the color spaces of all colored thermoplastics. Further analysis, including Fisher pairwise comparisons of one-way ANOVA, revealed that screw speed influenced the redness and hue of low-MFR PPCP, whereas die temperature affected the lightness and hue of high-MFR PPCP and ABS. Interestingly, the blueness and chroma of colored thermoplastics were minimally affected by both screw speed and die temperature. Notably, regardless of processing conditions, the flexural properties of colored thermoplastics remained comparable to the neat polymer when incorporated with ultramarine blue pigment masterbatch.

Exotic blue pigments in the polychrome interior of Yongle Taoist Temple: A case of international trade during the Yuan and Qing Dynasties

AbstractPrevious studies have established the use of various blue pigments, including both local and imported varieties, in the decoration of architecture in ancient China. However, the application of these pigments in local religious architecture has been understudied. In this study, the chemical analysis of ultramarine blue pigments was conducted on a mural painting retrieved from Yongle Taoist Temple in ancient China. The results showed that both imported and local pigments were used individually in the initial drawing period of the Yuan Dynasty (AD 1271–1368), whereas they were mixed in a later restoration in the Qing Dynasty (AD 1636–1912). Of particular significance, the analysis revealed the presence of lapis lazuli in a local religious relic of the Yuan Dynasty for the first time. Further analysis of the elemental proportions and associated minerals led to speculation about the origin of the lapis lazuli, which is believed to have come from Badakhshan, the northeastern region of Afghanistan, and been transported to Central China through the Silk Road. This finding shed light on the trade routes and usage of these pigments in the construction of religious architecture from the Yuan to the Qing dynasties.

SEM-FEG-EDS, GC-MS, EPR and Vibrational Spectroscopy Analysis of Materials in Baroque-Style Sculpture “Our Lady of Sorrows” from Garopaba, Santa Catarina, Brazil

Materials belonging to the polychromy and gilding of the sculpture ‘Our Lady of Sorrows, which belongs to the collection of a church in Garopaba, Santa Catarina, southern Brazil, were analyzed by multiple techniques. The analysis by μ-Raman and FTIR indicated the use of the ultramarine blue pigment, confirmed by EDS, with calcium carbonate observed in the base of preparation. The results show the use of gold leaf based on a gold and silver alloy, and the use of Armenian bole with clay and traces of manganese, as the base for fixing the gold leaf was characterized. GC-MS analysis suggested the use of plant oil in the painting process. Finally, the EPR analysis showed the presence of Fe3+, Mn2+ and organic radicals from the degradation of the binder, suggesting the formation of complexes with the degradation products, this being one of the first reports in this type of painting.

The Ability of the EPR MOUSE to Study Underpaintings

The possibility of using the electron paramagnetic resonance (EPR) mobile universal surface explorer (MOUSE) to study underpaintings is validated. The depth sensitivity of the EPR MOUSE is measured using an EPR standard, and is verified using three paramagnetic pigments in an acrylic binder under opaque acrylic layers of titanium white and lead white. The ability to distinguish and identify two layers of EPR signal-bearing pigments is shown using pairwise sets of ultramarine, Egyptian, and Han blue pigments in an acrylic binder. And finally, the spatial imaging capability is demonstrated using a printed design of magnetite black covered with a solid second layer of the pigment. These studies demonstrate that EPR spectroscopy with the EPR MOUSE is a viable method for studying paramagnetic and ferrimagnetic underlayers of pigments.

S 2 − and S3− radicals and the S42− polysulfide ion in lazurite, haüyne, and synthetic ultramarine blue revealed by resonance Raman spectroscopy

Abstract Taking advantage of the Raman resonance effect, we employed 405 and 532 nm excitations to (1) identify sulfur species present in lazurite, haüyne, and synthetic ultramarine blue pigments and (2) investigate the enigmatic ~485 cm–1 band found previously in Raman spectra of lazurite and haüyne collected with 458 nm excitation. In spectra of lazurite and haüyne, bands of the sulfate ion and S2− and S3− radicals can be seen. Spectra collected using 405 nm excitation show the enhancement of the intensity of ν1(S2−) band and its nν1 (n ≤ 7) progression. Spectra collected using 532 nm incident light show the enhancement of intensity of ν1(S3−), ν2(S3−), and ν3(S3−) bands and the nν1 (n ≤ 9) and ν2 + nν1 progressions of the ν1(S3−) band. In spectra collected with 405 nm excitation, we also found features that we ascribe to the S42− polysulfide ion. These include the ν1 symmetric S-S stretching band at ~481 cm–1, the ν2 symmetric S-S stretching band at ~443 cm–1 (only present in spectra of some lazurite samples), the ν3 symmetric S-S bending at 223 cm–1 and the nν1 (n ≤ 5) and nν1+ν3 progressions of the ν1(S42−) band. We observed that under laser illumination, the S42− polysulfide ion rapidly decomposes into two S2− radicals in lazurite while it remains stable in haüyne. In spectra of synthetic ultramarine blue pigments, only features of S2− and S3− radicals were observed. Finally, we verified the identity of the radical and polysulfide ions with ab initio molecular dynamics calculations. We conclude that Raman resonance spectroscopy is a powerful qualitative method to detect polysulfide and sulfur radical species with concentrations below the detection limit of conventional analytical techniques. Owing to the high stability of S42− in haüyne, this mineral structure appears promising as a host material for S42− entrapment, making it potentially useful for applications in optoelectronics.

Is There an International Klein Pink?

Yves Klein (1928–1962) is best known for his intensely blue monochromatic works made with International Klein Blue (IKB), a synthetic ultramarine blue pigment bound in a poly(vinyl acetate) binder. However, he also made monochromes in other colors, including red and pink, the pigments of which have never been elucidated. Analysis of one sculpture, three paintings, and one screenprint by micro-Fourier transform infrared spectroscopy (µ-FTIR), Raman and surface-enhanced Raman (SERS) spectroscopies, portable X-ray fluorescence spectroscopy (p-XRF), and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX), revealed that Klein used, knowingly or unknowingly, a variety of pink and red pigments, including Para Red, rhodamine 6G, rhodamine B, eosin Y, and alizarin lakes. The unexpected variety of pigments contrasts with his use of a single blue pigment and suggests he may not have held a singular vision of what constituted an iconic red or pink color.

Cosmetic effects of red-light reflection by ultramarine blue pigment.

Inorganic pigments used as colouring agents in cosmetics (especially foundations) have many advantages over organic pigments, such as better opacity, weather and chemical resistance and lower cost. However, the types used in cosmetics are very limited, with various kinds of red, yellow and black iron oxide along with white titanium dioxide being the main materials. Ultramarine blue (UB) as a blue pigment and chromium oxide as a green pigment are also sometimes used in cosmetics. In this study, we focus once again on UB and reexamine the possibility of expanding the colour gamut using UB instead of black pigment and creating other optical cosmetic effects. The effects of using UB were measured using spectroscopic instruments to determine the colour parameters when applied on artificial skin. The appearance of the product when applied to the human face was also verified both in terms of human appearance evaluation by an expert (esthetician) and numerical evaluation using imaging spectrometer measurements. The verified results showed that, at least in the colour range targeting Asian people, UB could not create a new colour gamut, but it was clear that UB could impart an optical effect that produced a beautiful skin effect on the face. This was remarkable both in the evaluation of human appearance and in the spectral measurement results, which confirmed the phenomenon "red-light makes skin look beautiful," which has been variously reported since the 2000s, using a different approach. We have discovered a new possibility that UB, widely recognized as a pigment, is involved not only in colour tone but also in optical effects that contribute to the goal of beautiful skin, i.e. hiding skin wrinkles, eliminating unevenness of colour and improving skin homogeneity.

Synthesis of high acid-resistant ultramarine blue pigment through coal gangue, industrial zeolite waste and corn straw waste recycling

The massive stacking of the coal gangue (CG) in the coal mining process, discarded industrial zeolite waste (IZW) and agricultural corn straw (CS) has caused serious environmental pollution and resource waste. To achieve the recycling of solid waste, an economical method for synthesizing ultramarine blue pigment using a two-step calcination process of the CG/IZW/Na2CO3/S/CS with the mass rates of 1.50: 0.50: 2.50: 3.50: 1.00 (the first stage at 400°C for 0.50 h and the second stage at 900°C for 2.00 h) is proposed in this paper. The structure and composition of the synthesis ultramarine blue pigment were characterized by XRD, FT-IR, Raman, as well as SEM technologies, and results showed it had a sodalite structure containing S3− and S2− radicals. Furthermore, SiO2 (1.20 mL of tetraethyl orthosilicate (TEOS) as the precursor and 4.50 mL of NH3•H2O as the catalyst) coated the synthesis ultramarine blue pigment (1.00 g) was successfully synthesized by sol-gel technique to improve the acid resistance of the pigment (pH=2.50-3.00). This new method of preparing ultramarine blue pigments not only achieves resource reuse at a low cost but also improves the acid rain resistance of the pigments.

Multisensor hyperspectral imaging approach for the microchemical analysis of ultramarine blue pigments

This work presents a multisensor hyperspectral approach for the characterization of ultramarine blue, a valuable historical pigment, at the microscopic scale combining the information of four analytical techniques at the elemental and molecular levels. The hyperspectral images collected were combined in a single hypercube, where the pixels of the various spectral components are aligned on top of each other. Selected spectral descriptors have been defined to reduce data dimensionality before applying unsupervised chemometric data analysis approaches. Lazurite, responsible for the blue color of the pigment, was detected as the major mineral phase present in synthetic and good quality pigments. Impurities like pyrite were detected in lower quality samples, although the clear identification of other mineral phases with silicate basis was more difficult. There is no correlation between the spatial distribution of the bands arising in the Raman spectra of natural samples in the region 1200–1850 cm−1 and any of the transition metals or rare earth elements (REE). With this information, the previous hypothesis (based on bulk analysis) attributing these bands to luminescence emissions due to impurities of these elements must be revised. We propose the consideration of CO2 molecules trapped in the cages of the aluminosilicate structure of sodalite-type. Additionally, correlation between certain Raman features and the combined presence of Ca, P, and REE, in particular Nd, was detected for the lowest quality pigment. Our results highlight the usefulness of fusing chemical images obtained via different imaging techniques to obtain relevant information on chemical structure and properties.

On the Two Working Palettes of Almada Negreiros at DN Building in Lisbon (1939–1940): First Analytical Approach and Insight on the Use of Cd Based Pigments

This paper reports the first analytical approach carried out on two working palettes by Portuguese modernist master Almada Negreiros, found in 1991 behind old wood cabinets at the DN building in Lisbon. This is the only known occasion Almada left behind the color experiments done before starting to paint in the nearby walls and as such, it is a unique opportunity to analyze the materials and painting techniques that were originally used. The analytical setup comprised in loco technical photography in Vis, UVF and NIR; p-OM, spectrophotometry in Vis and h-EDXRF, complemented by OM-Vis, µ-FT-IR and VP-SEM-EDS of painting micro-samples and pigments in powder form. Preliminary results suggested the use of fresco painting technique and revealed some technical details, such as the use of a coarse lime sand finishing mortar mixed with natural vegetable fibers, and the extensive use of cadmium-based pigments that were not commonly used (or even recommended) in an alkaline environment. The Cd pigments were used alone or in mixtures with Fe based pigments in the warm hues and with cobalt and ultramarine blue pigments in some green paint layers. No clear evidence of organic materials that could have been used as binders was detected.

Ellipsoid ultramarine blue pigment with high near-infrared reflectance

In this work, an ultramarine blue pigment with high near-infrared (NIR) reflectance is achieved by adjusting the content of Na2CO3 during the preparation process. The acquired pure ultramarine blue (PU) pigment has a relatively uniform ellipsoid morphology with a narrow size distribution ranging from 1 to 3 μm. More importantly, the PU pigment shows a NIR reflectance of 80.67 %, which is higher as compared to those previously reported (∼72 %). The thermal stability of the sample is also evaluated by thermogravimetric-differential scanning calorimeter (TG-DSC), and the result shows that the PU pigment is relatively stable when the temperature does not exceed 800℃. In addition, the effectiveness of its ability to cooling the substrate is investigated by applying the PU pigment onto an Al plate. Interestingly, the inner surface temperature of the Al plate coated with the PU pigment reveals 0.8∼2℃ lower than its counterpart coated with the commercial pigment. Thus, this result shows the potential of using the PU pigment as a high NIR reflective material for thermal management.

Characterization of the Alphabet Reform Painting

The Alphabet Reform painting which shows Ataturk teaching the new alphabet is important for the history of the Republic of Turkey. This painting was made by Nazmi Ziya GÜRAN in 1933. The painting is now maintained by the Ministry of Interior. In this work, the Alphabet Reform painting was analyzed for characterization and restoration purposes. The fabric of the canvas, pigments (organic-inorganic) and the binder of paint were characterized by Fourier Transform infrared spectroscopy-attenuated total reflectance (ATR-FTIR), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) and high-performance liquid chromatography-coupled with diode array detection (HPLC-DAD) analysis methods. The CIEL*a*b* color parameters of the paint were determined by color measurement spectrophotometer. According to the results; canvas was found to be of fibers of vegetable origin and the binders were determined to be linseed oil and dammar varnish. Red alizarin (madder lake organic pigment) and dark blue ultramarine pigments were detected as the organic pigments while CdS (yellow), Pb red (flesh color), PbCO3 (white), ZnO (white), BaSO4 (white), FeO (brown) and Cr2O3 (green color) were detected as the inorganic ones.

Natural or synthetic? Simultaneous Raman/luminescence hyperspectral microimaging for the fast distinction of ultramarine pigments

Genuine ultramarine has been one of the most precious blue pigments employed since ancient times. It used to be obtained by crushing and grinding the lapis lazuli rock and selectively extracting the blue mineral lazurite. Since 1828, when it was produced the synthetic version, the use of this much less expensive material became widespread and synthetic ultramarine blue replaced the natural one in painting palettes. The distinction between natural and synthetic ultramarine is, therefore, an important goal in authentication issues. Here, we present a hyperspectral microRaman imaging analysis, complemented with the characterization of ultramarine pigment samples in terms of colour, elemental composition and identification of crystalline phases by means of fiber optics reflection spectroscopy (FORS), X-Ray Fluorescence (XRF) and X-Ray diffraction (XRD), respectively. We show that a characteristic luminescence signature, easily detected in the course of standard Raman spectroscopic analysis using 785 nm as excitation, is indicative of the natural origin of the ultramarine blue pigments. Furthermore, simultaneous Raman/luminescence hyperspectral microimages allow the distinction between natural pigments of different quality thanks to the different intensity and spatial distribution of the lazurite characteristic band at 548 cm−1 and those of the luminescent impurities in the region between 1200 and 2000 cm−1. The establishment of a range of quality between different samples of lapis lazuli was also attempted taking into account the variations in the intensity of the Raman bands located at 548 cm−1 and 1286 cm−1. Finally, the feasibility of using the simultaneous Raman/luminescence features for authentication of ultramarine blue in a real historical context, even with non-invasive investigations, is illustrated with examples of different types of blue decorations from several halls of the Alhambra monumental ensemble, in Granada.

Beyond the visible: The Viterbo Crucifixion panel painting attributed to Michelangelo Buonarroti

The painting object of the present work, currently exposed in the Museum of Colle del Duomo in Viterbo (Italy), has been dated back by art historians to the 16th century and it owes its relevance to a still discussed attribution to Michelangelo Buonarroti. For this reason, art historians and the responsible curator of the Museum commissioned scientific investigations to support and explain their hypothesis about the painting attribution and dating. Here we report the results of two sets of investigation: diffuse reflectance hyperspectral imaging and X-ray fluorescence spectroscopy of the painting; radiocarbon dating and identification of the panel wood. The hyperspectral dataset, coupled with X-ray fluorescence spectra on selected analysis points, reveals the presence of precious ultramarine blue and vermillion pigments, confirming the importance of the painting committer. Wood analysis and radiocarbon dating by wiggle matching technique revealed that the botanical species used for the panel is Cypress (Cupressus sempervirens L.), and enabled dating the painting around AD 1500± 25, providing to art historians a further element for the attribution of the artwork.

Preparation and characterisation of photocatalytic pigments for architectural mortar based on ultramarine blue

Architectural mortar is used in the building sector when aesthetic surface value is required and therefore, these surfaces present a great potential to be used as a solution for the reduction of atmospheric pollution. In the present work, an inorganic ultramarine blue pigment has been modified to provide the mortars with colour and photocatalytic properties, simultaneously. To modify the pigment, a sol–gel coating based on titanium n-butoxide precursor has been applied on its surface. The influence of different parameters affecting the coating formation, such as the pH and titanium weight content of the sol–gel reactants, has been studied. Moreover, the formation of a coating on the pigment’s surface with several amounts of TiO2 anatase nanoparticles has also been explored. A pigment with better photocatalytic properties has been obtained at pH = 12 applying a coating based on titanium n-butoxide precursors (Ti precursor/pigment weight ratio = 0.5) with 2 wt.% of titania anatase nanoparticles, maintaining the original pigment colour. Moreover, mortars with the new pigment present higher flexural strength and similar compressive strengths than non-modified mortars ensuring the applicability of the pigment in the building sector.

Understanding the influence of microbial contamination on colour alteration of pigments used in wall paintings—The case of red and yellow ochres and ultramarine blue

AbstractThis article reports biocolonization assays carried out on yellow and red ochres and ultramarine blue pigments. These pigments have been most commonly used in traditional limewash of heritage buildings from southern Portugal (Alentejo) and, in the case of the yellow and red ochres, also in historical decorative wall paintings since Roman times. The research aim was to assess the potential role played by microorganisms in colour alterations observed in indoor and outdoor paint layers for conservation purposes.The assays accomplished several microorganisms previously isolated from degraded wall paintings with signs of biocontamination. The results show that apart from the clear physical stress induced in paint layers by the biometabolic activity, filamentous fungi, yeast, and bacteria are capable of inducing discoloration (in particular, the fungus Aspergillus niger). Raman analysis corroborates their active role in painting discolouration. This methodology, applied to bioprocesses, can be used as noninvasive methodology to signal microbial involvement.

Preparation and characterization of ultramarine blue pigments from fly ash by using the X-ray photoelectron spectroscopy (XPS) for the determination of chemical states of sulphur in chromophores

Abstract Natural ultramarine (UMB) pigments have been of broad use in the past and present in their natural form (lapis lazuli). They belong to the group of mineral pigments characterized by the sodalite structure and coloured sulphur species (chromophores) encapsulated inside. Nowadays, there is an urgent need for their cheaper analogues synthetized from other minerals or, if possible, from waste materials. At the same time, a better understanding of chemical interactions of the rather complex constituents of the UMB synthesis is needed with the help of sophisticated spectroscopic techniques of surface analysis. In this preliminary study, the novel X-ray photoelectron spectroscopy (XPS) is applied to determine the content and chemical state (oxidation and binding) of sulphur and other elements of a fly ash and other constituents used to prepare synthetic UMB pigments. The main aim was to elucidate a possible connection of these original parameters (especially sulphur-based chromophores) with a final colour of the UMB pigments (green, blue, reddish blue, pink, violet, red and greenish blue). The results were compared with these from more traditional ones: Raman and Infrared spectroscopy.

A nondestructive method of identifying pigments on canvas using low frequency electron paramagnetic resonance spectroscopy

ABSTRACTElectron paramagnetic resonance (EPR) spectroscopy is a useful analytical tool for studying objects with cultural heritage significance. It is generally thought of as a destructive spectroscopy, owing to the small sample size, and thus not used to study paintings. We demonstrate that a form of this spectroscopy known as low frequency EPR spectroscopy can be used to nondestructively identify ultramarine blue, Egyptian blue, Han blue, rhodochrosite, blue vitriol, terracotta red, charcoal, and coal pigments in a linseed oil paint on canvas.